Rotational ThromboelastometryEdit

Rotational thromboelastometry (ROTEM) is a viscoelastic hemostatic assay that provides a real-time, dynamic picture of coagulation in whole blood. By monitoring how the blood sample changes from a liquid to a clot and then to eventual dissolution, ROTEM yields a set of curve-based parameters that reflect clot formation, strength, and fibrinolysis. As a point-of-care technology, ROTEM can produce actionable information within minutes, enabling targeted hemostatic therapy rather than blanket transfusion strategies. For clinicians, this approach contrasts with conventional coagulation tests that measure isolated time-to-clot parameters in plasma and may lag behind the patient’s evolving coagulopathy. See for example viscoelastic testing and point-of-care testing discussions, and the relation to thromboelastography in the broader family of coagulation assays.

ROTEM works alongside other viscoelastic approaches to coagulation assessment, such as thromboelastography, but emphasizes reagents and pathways that illuminate different aspects of the coagulation system. Reagents are used to activate specific pathways (for example, tissue factor–triggered pathways or intrinsic pathway activation), and the device reports a series of readouts that together form a coagulation profile. This profile can capture information about platelet contribution, fibrin-based clot strength, and fibrinolysis, which can be pivotal during major bleeding, surgery, or trauma. See discussions of EXTEM, INTEM, FIBTEM, APTEM, and NATEM for the component assays that ROTEM platforms commonly employ.

Technical basis

ROTEM is a platform that measures viscoelastic properties of blood as coagulation proceeds. It provides a graphical representation of clot formation and dissolution over time. See viscoelastic testing for a broader context of how these tests relate to other modern coagulation assessments.
The core readouts typically include clotting time (CT), clot formation time (CFT), and maximum clot firmness (MCF), with additional metrics such as early amplitude at fixed time points (e.g., A5/A10) and markers of fibrinolysis. Depending on the system, lysis indices (e.g., LI30/LI60) may be reported to quantify how much clot strength remains over time.
The assay palette includes targeted pathways: EXTEM (extrinsic pathway activation via tissue factor), INTEM (intrinsic pathway activation), FIBTEM (fibrin-based contribution by inhibiting platelets), and APTEM or NATEM (additional options to probe fibrinolysis or native coagulation). See EXTEM, INTEM, FIBTEM, APTEM, and NATEM for more detail.

Operation and interpretation

Sample handling: ROTEM is typically run on citrated whole-blood samples, and results are generated rapidly, often within 5–15 minutes of loading. The speed and breadth of data are designed to support bedside decision-making in settings where time is critical, such as in the operating room or emergency department. See point-of-care testing for how rapid coagulation data interacts with clinical workflows.
Clinical interpretation: Interpreting ROTEM results requires understanding how each assay reflects components of coagulation—coagulation factor activity, platelet function, fibrinogen contribution, and fibrinolysis. Clinicians use predefined thresholds and algorithms, sometimes embedded in institutional protocols, to decide on targeted interventions such as fibrinogen supplementation, platelet transfusion, antifibrinolytics, or the use of specific factor concentrates. See discussions of transfusion medicine and massive transfusion protocol for context on how these results feed into broader treatment plans.
Comparison with conventional tests: ROTEM complements standard coagulation testing (e.g., prothrombin time/activated partial thromboplastin time) by offering a composite, dynamic view rather than isolated time-to-clot values. This can be especially valuable in complex bleeding scenarios where multiple hemostatic pathways are involved.

Clinical applications

Trauma and hemorrhagic shock: In major bleeding, ROTEM-guided resuscitation aims to reduce exposure to blood products and accelerate corrective therapy. The real-time profile can help clinicians decide whether to administer fibrinogen, platelets, or antifibrinolytics. See trauma and massive transfusion protocol for related matters.
Cardiac surgery: After cardiopulmonary bypass, ROTEM can help manage coagulopathy and bleeding, guiding product use and adjuncts to restore hemostasis. See cardiac surgery for broader context.
Liver transplantation and hepatic surgery: Coagulopathy in liver disease or during transplantation is complex; ROTEM data can inform targeted therapy to optimize clot formation while minimizing transfusion-related risks. See liver transplantation and liver surgery discussions for related topics.
Obstetric hemorrhage and postpartum bleeding: In settings of pregnancy-related bleeding, ROTEM has been used to tailor hemostatic therapy quickly, aligning with protocols designed to reduce maternal morbidity. See postpartum hemorrhage for related material.
Other surgical and critical care contexts: ROTEM is employed in various settings where rapid coagulation assessment is advantageous, including orthopedic surgery and major vascular procedures. See surgery and critical care topics for broader connections.

Evidence and controversies

Evidence for benefit: A number of systematic reviews and meta-analyses across settings such as trauma, cardiac surgery, and liver transplantation suggest that ROTEM-guided therapy can reduce exposure to allogeneic blood products and may shorten time to hemostasis. In some settings, there is also evidence of improved clinical outcomes or resource utilization, though results are not uniformly positive across all trials. See systematic review discussions and domain-specific articles on ROTEM in trauma, cardiac surgery, and liver transplantation.
Mortality and outcomes: While reduced transfusion and faster hemostasis are consistently reported benefits, demonstration of mortality reduction is more variable, with results influenced by study design, patient population, and concomitant therapies. Critics caution against overgeneralizing benefits from heterogeneous studies and emphasize the need for well-designed randomized trials in specific contexts. See debates around evidence-based medicine and randomized controlled trial methodology.
Cost and implementation: The upfront costs of ROTEM devices, disposables, and training are nontrivial. Proponents argue that reduced transfusion needs, shorter hospital stays, and streamlined blood-bank operations can offset expenses in centers with high bleeding risk. Critics highlight the dependence on institutional protocols, operator skill, and the variability of evidence across settings. See discussions of health economics and cost-effectiveness in relation to transfusion medicine.
Standardization and interpretation: A recurring theme is the need for standardization of testing platforms, reagents, and interpretation thresholds. Differences between ROTEM systems and between centers can complicate cross-study comparisons and guideline development. This underlines why many professional bodies advocate institution-specific protocols paired with ongoing training. See entries on clinical guidelines and medical training for related considerations.
Controversies and criticisms: Some critiques focus on the risk that reliance on viscoelastic testing could delay therapy in rapidly evolving bleeds if not integrated with clinical judgment. Others caution against attributing improvements to ROTEM without accounting for confounders such as overall bleeding control, timing of antifibrinolytic therapy, and concomitant surgical hemostasis. From a policy and practice perspective, the debate often centers on balancing rapid, targeted therapy with the realities of cost, training, and evidence quality. See the broader discussions under medical ethics and health policy as they relate to point-of-care testing and resource allocation.
Self-contained governance: Institutions that adopt ROTEM typically establish protocols that specify when testing should drive transfusion or coagulopathy management decisions, aiming to minimize variability and ensure timely care. See clinical governance and quality improvement topics for related framework discussions.

Technological evolution and future directions

Device improvements and automation: Newer ROTEM platforms emphasize automation, simplified workflows, and enhanced integration with electronic medical records and transfusion algorithms. See medical technology discussions for broader perspectives on device evolution.
Integration with precision medicine: As data accumulate, there is interest in refining interpretation algorithms, incorporating pharmacokinetic considerations for anticoagulants, and tailoring hemostatic therapy to individual patient profiles. See precision medicine and medical informatics for related threads.
Broader adoption and guidelines: Ongoing clinical trials and guideline updates continue to shape the role of ROTEM in perioperative and emergent care, with emphasis on context-specific benefits, cost-effectiveness, and workforce training. See clinical guidelines and medical research for adjacent topics.